The invention relates to a flat miniature dynamoelectric machine which may be used as either motor or generator or the like. A flat miniature dynamoelectric machine is known which has a rotor of a reduced thickness and a permanent magnet which are disposed in axial alignment therewith, thus minimizing the axial thickness of the machine. Such a flat miniature dynamoelectric machine may be operated as a motor for use in a small size electrical instrument such as a portable cassette tape recorder. In a conventional flat miniature dynamoelectric machine, the whole commutator is disposed on one side of the rotor, so that there must be provided separate spaces for the provision of the rotor and the commutator, resulting in an increased overall space requirement.